Plasma Nitriding of Titanium Alloy Ti5Al4V2Mo

Nitriding of highly alloyed titanium material Ti5Al4V2Mo was performed at 500, 600,700,800, 900°C in the mixture of 50±10% Ar + 50±10% N2 at 300-450 Pa (3-4.5 mbar) for 3-4 hours. The hardness at the surface increased with temperature, and at 900 °C it was 1.7 times higher than that of the untreated material. The hardness decreased with the depth, and the thickness of the hardened layer was 30-50 μm at 900 °C. The phase composition is very complex, comprising various Ti phases, various titanium nitride phases, and titanium dioxide.